Drip Legs

Hi Everyone,
With regard to water heaters and furnaces, are drip legs still required? If so, does the flex line connecting the unit to the solid piping qualify if it drops down and comes up vertically to the fitting on the unit?
Thanks so much,

Answer to first is that it depends on your location.
Answer to second is that does not sound correct.


Drip legs are code for installaton of water heaters in Chicago. The reason behind the drip leg is that there is moisture in the gas supplied from the piping. When the drip leg has been omitted you risk allowing the moisture to pass through the regulator and able to burn through the burner assembly. The gas has moisture in it because it does not have a drip leg and that moisture turns to a caustic steam that adheres to the bottom of the storage tank and can cause premature rusting. The burner and thermal coupling can be changed but the storage tank cant and will cause the water heater to age prematurely. I call all missing drip legs.

we do not put moisture in the gas here…so we do not get the dreaded “Caustic Steam”. :smiley:


Ya… Arizona has that “dry heat” thing going on! :shock::p:twisted:

Thats awesome~

Not required here also

Some manufactures require it

You know the device. You know what it does. You know what can happen without it.

Who cares if it is “required” or not?!

OK. Mr Licensed plumber, This is a question I have been asking for 20 years here in Chicago, roof top units drip legs, yes or no. I have two different answers from Peoples gas. I was told no by a plumber 20 years ago, water would freeze and burst drip.leg what say you.

I make a note of it, but i am getting tired of contractors whining;-)